// pages/waveimage/waveimage.js
var ctx=null;
var factor={
              speed:.008,  // 运动速度，值越小越慢
              t:0    //  贝塞尔函数系数
            };


var timer = null;  // 循环定时器

Page({
  data:{
    style_img:''
  },
  onLoad:function(options){
    // 页面初始化 options为页面跳转所带来的参数
    wx.setNavigationBarTitle({
      title: options.title,
      success: function(res) {
        // success
      }
    })
     ctx = wx.createCanvasContext('canvas_wi')
     this.startTimer();
  },

  onUnload:function(){
    if(timer!=null){
        cancelAnimationFrame(timer);
    }
    
  },

  drawImage:function(data){
    var that = this
    var p10= data[0][0];   // 三阶贝塞尔曲线起点坐标值
    var p11= data[0][1];   // 三阶贝塞尔曲线第一个控制点坐标值
    var p12= data[0][2];   // 三阶贝塞尔曲线第二个控制点坐标值
    var p13= data[0][3];   // 三阶贝塞尔曲线终点坐标值

    var p20= data[1][0];
    var p21= data[1][1];
    var p22= data[1][2];
    var p23= data[1][3];

    var p30= data[2][0];
    var p31= data[2][1];
    var p32= data[2][2];
    var p33= data[2][3];
    
    var t = factor.t;

    /*计算多项式系数 （下同）*/    
    var cx1 = 3*(p11.x-p10.x);
    var bx1 = 3*(p12.x-p11.x)-cx1;
    var ax1 = p13.x-p10.x-cx1-bx1;

    var cy1 = 3*(p11.y-p10.y);
    var by1 = 3*(p12.y-p11.y)-cy1;
    var ay1 = p13.y-p10.y-cy1-by1;

    var xt1 = ax1*(t*t*t)+bx1*(t*t)+cx1*t+p10.x;
    var yt1 = ay1*(t*t*t)+by1*(t*t)+cy1*t+p10.y;

    /** ---------------------------------------- */
    var cx2 = 3*(p21.x-p20.x);
    var bx2 = 3*(p22.x-p21.x)-cx2;
    var ax2 = p23.x-p20.x-cx2-bx2;

    var cy2 = 3*(p21.y-p20.y);
    var by2 = 3*(p22.y-p21.y)-cy2;
    var ay2 = p23.y-p20.y-cy2-by2;

    var xt2 = ax2*(t*t*t)+bx2*(t*t)+cx2*t+p20.x;
    var yt2 = ay2*(t*t*t)+by2*(t*t)+cy2*t+p20.y;


  /** ---------------------------------------- */
     var cx3 = 3*(p31.x-p30.x);
    var bx3 = 3*(p32.x-p31.x)-cx3;
    var ax3 = p33.x-p30.x-cx3-bx3;

    var cy3 = 3*(p31.y-p30.y);
    var by3 = 3*(p32.y-p31.y)-cy3;
    var ay3 = p33.y-p30.y-cy3-by3;

    /*计算xt yt的值 */
    var xt3 = ax3*(t*t*t)+bx3*(t*t)+cx3*t+p30.x;
    var yt3 = ay3*(t*t*t)+by3*(t*t)+cy3*t+p30.y;
    factor.t +=factor.speed;
    ctx.drawImage("../../images/heart1.png",xt1,yt1,30,30);
    ctx.drawImage("../../images/heart2.png",xt2,yt2,30,30);
    ctx.drawImage("../../images/heart3.png",xt3,yt3,30,30);
    ctx.draw();
    if(factor.t>1){
        factor.t=0;
        cancelAnimationFrame(timer);
        that.startTimer();
    }else{
        timer =requestAnimationFrame(function(){
            that.drawImage([[{x:30,y:400},{x:70,y:300},{x:-50,y:150},{x:30,y:0}],[{x:30,y:400},{x:30,y:300},{x:80,y:150},{x:30,y:0}],[{x:30,y:400},{x:0,y:90},{x:80,y:100},{x:30,y:0}]])
      })
    }
   
  
  },

    
  onClickImage:function(e){
    var that = this
      that.setData({
          style_img:'transform:scale(1.3);'
      })
      setTimeout(function(){
            that.setData({
              style_img:'transform:scale(1);'
            })
      },500)
  },

  startTimer:function(){
    var that = this
       that.setData({
          style_img:'transform:scale(1.3);'
      })
      setTimeout(function(){
            that.setData({
              style_img:'transform:scale(1);'
            })
      },500)
        that.drawImage([[{x:30,y:400},{x:70,y:300},{x:-50,y:150},{x:30,y:0}],[{x:30,y:400},{x:30,y:300},{x:80,y:150},{x:30,y:0}],[{x:30,y:400},{x:0,y:90},{x:80,y:100},{x:30,y:0}]])
              
  }



})